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North Pacific armorhead (Pentaceros wheeleri) was previously considered rare and was sporadically captured in the eastern and western North Pacific. In 1967, an exploratory bottom trawler of the Soviet Union discovered large aggregations of this species associated with the summits of the Southern Emperor—Northern Hawaiian Ridge (SE-NHR) seamounts. The large trawl catches attracted the participation of commercial bottom trawl fleets of the Soviet Union, Japan, and Korea. Although exploratory fisheries and scientific surveys collected some basic information on the biology of this species, large uncertainties remain due to its peculiar life history. Here we describe the current knowledge and information gaps for the biology and ecology of this species through a review of original scientific literature. The life cycle of this species consists of pelagic and demersal stages. Juvenile and immature fish are widely distributed over the subarctic surface waters of the central and eastern North Pacific Ocean. P. wheeleri undergo a protracted initial pelagic phase of 2 yr (perhaps up to 4.5 yr) in the epipelagic zone. Subadult fish ≥25 cm in fork length recruit to the summits and upper slopes of the SE-NHR seamounts in spring or summer. There are large episodic fluctuations in recruitment to the seamounts that are not predictable or understood and these events obscure the determination of a spawner-recruit relationship. After seamount recruitment, body growth ceases, and the demersal reproductive phase begins. Spawning has only been confirmed around SE-NHR seamounts and occurs from November to February. Large fluctuations in recruitment, difficulties in determination of age and other life history parameters, and the occurrence of fishing grounds on the high seas make the stock assessment and management of this species challenging.
Lake Kutubu is a tropical freshwater lake that is internationally renowned for its biodiversity, 12 endemic species of fish, wetlands, and swamp forests. This study reports on a fish kill and the introduction of exotic species, and it assesses impacts on fish stocks and the artisanal fishery. The fish kill, which began in January 2013 and lasted for 6 months, was characterized by fish pathologies consistent with epizootic ulcerative syndrome. Sleeper gobies and gudgeons (i.e., Mogurnda variegata Nichols, Mogurnda furva Allen & Hoese, Mogurnda kutubuensis Allen & Hoese, and Oxyeleotris fimbriata [Weber]) had more obvious signs of disease than did Hephaestus adamsoni (Trewavas), Melanotaenia lacustris Munro, and Craterocephalus lacustris Trewavas. The event coincided with an inflow of a plume of white particulates from the northeast, where hydrocarbon companies carried out extensive horizontal drilling in 2012–2013. Six months after the event, the main species caught by fishers were Cherax papuanus Holthuis (16%), H. adamsoni (55%) and M. lacustris (28%), which is different from the mix of species found in previous surveys of 1995 and 1997. The recent fish kill, as well as socioeconomic changes, substantially reduced the fish catch and fishing effort. Small-scale fish farmers began raising the genetically improved farmed tilapia strain of tilapia (Oreochromis niloticus Linnaeus) and common carp (Cyprinus carpio Linnaeus) in earthen ponds in 2009 and introduced water hyacinth (Eichhornia crassipes [Mart.] Solms) as a food for these fish. Heavy rains in 2010–2012 released farmed fish into the lake, and in May 2015, fishers report that the fish catch is dominated by tilapia. Improved strategies are required to educate stakeholders, assess fish stocks, and protect biodiversity by reducing anthropogenic impacts.
The spatial and temporal distribution pattern of stranded cetaceans in Korean waters was investigated for the conservation and management of cetaceans in this area. A total of 154 cetacean stranding events consisting of 12 species were recorded in Korean waters from 1997 to 2004 by the Korea Coast Guard. A total of 4 species, the minke whale (Balaenoptera acutorostrata) (n = 43), Unless porpoise (Neophocaena asiaeorientalis) (n = 43), Stejneger's beaked whale (Mesoplodon stejnegeri) (n= 15), and common dolphin (Delphinus delphis) (n= 11), accounted for 73% of the stranded cetaceans. The majority of stranding events took place in the East Sea (n = 99; 64%) followed by the Korea Strait (n = 48; 31%) and the Yellow Sea (n = 7; 5%). The hot spots of stranding events in Korean waters were Pohang (18%), Busan (9%), and Goseong (8%). The number of stranding events increased following the establishment of the bycatch/stranding reporting system in 1997, with a steep increase in the number of stranding events after 2000. There were more stranding events in spring and summer (66%) than in fall and winter (34%), with a peak from March to July (51%). This is the first report on the spatial and temporal distribution pattern of stranded cetaceans in Korean waters. Future work on strandings in Korean waters should strive to investigate the causes of these strandings.
Understanding the distribution range across the life history of endangered animals is crucial for effective conservation and management planning. However, endangered migratory green turtles with straight carapace lengths (SCLs) of <35 cm have been rarely observed in the northwestern Pacific. Information on wild green turtles with an SCL of <35 cm in this region is therefore scarce. Historically, four individuals with an SCL of <35 cm from the Japanese coasts and an oceanic area in Japan have been reported. From 2011 to 2013, we collected nine turtles with an SCL of <35 cm from Japanese coasts and coastal waters. We reviewed the existing literature and compiled records of newly collected individuals and their mitochondrial deoxyribonucleic acid haplotypes. The combined total of 13 turtles had SCLs ranging from 6.2 to 28.0 cm. Molecular analyses of nine newly collected turtles indicated that most individuals had hatched at green turtle nesting sites on the Ogasawara Islands and islands in the Ryukyu Archipelago. These results suggest that early juvenile green turtles inhabit Japanese waters, and some turtles with an SCL of <35 cm appear to have remained in Japanese waters after leaving their natal beaches in Japan without drifting with the prevailing oceanic currents to central north or eastern Pacific regions. Although the sample size in the present study was small, this is a first step in constructing comprehensive conservation and management plans for green turtles in the northwestern Pacific.
Introduced goats and European rabbits have caused devastating effects on island vegetation, and many successful efforts to eradicate these introduced animals have taken place mainly since the 1950s. Yet, a comprehensive review of vegetation response to goat and rabbit eradications is lacking. We conducted a literature search for articles on vegetation assessments before and after eradications. We conducted two kinds of reviews of species richness and cover response to eradication: a literature review for studies that provided qualitative or species-by-species responses to eradications and a meta-analysis on quantitative vegetation cover and species richness data. A key finding from our literature search was a significant information gap in the reporting of vegetation responses after eradication. Of over 200 successful island eradications that have been conducted since the 1800s, we found only 23 eradication studies that met our criteria for inclusion in the present analysis. Plant richness and vegetation cover increased more often than they decreased after eradication. Results varied according to region, herbivore type, habitat, and vegetation type, suggesting island-specific circumstances influence responses. The effect of eradication on Sub-Antarctic tundra species richness and on tropical vegetation percentage cover was higher than for other types of vegetation. Few cases differentiate responses of native versus exotic plant species, despite native biodiversity protection being one common goal of introduced herbivore eradication. We strongly recommend before and after eradication vegetation monitoring to understand how island ecosystems respond to eradication. Continuous monitoring would provide guidance on whether active restoration strategies need to be implemented to recover key native species and on the development of a general model of expected vegetation response, which is an integral first step to accelerate our predictive ability of vegetation responses.
During a sampling program focused on Anthozoa from Ecuador, the caprellid Aciconula acanthosoma was found attached to gorgonians of the genus Leptogorgia collected in Machalilla National Park in November 2012 and June 2013 at depths between 15 and 20 m. The present study represents the first record of A.acanthosoma for Ecuador, increasing its distribution range 3,000 km southward.
A new bivalve species of the genus PinnaLinnaeus, 1758, is described from shallow water off the coast of Easter Island, southeastern Pacific Ocean. Pinna rapanui sp. n. has a small, broad, slightly angulated shell with a sculpture of commarginal growth lines and prominent radial ribs decorated by almost tubular, perpendicularly erect spines. This species is the 249th marine molluscan species found in Easter Island waters, and it is, by far, the largest bivalve species living around the island. A Polynesian origin of this species is suggested; however, its definite affinities with Indo-Pacific or South American fauna are still unknown.
Kosrae, the easternmost high island of Micronesia, is a 110 km2 volcanic island rising up to 630 m above sea level. It is seldom visited by birders and ornithologists because it is small, isolated, and lacks any previously recognized extant endemic bird species. We review the history of research on the island's avifauna and summarize the status of each species, including documentation for six new species: Northern Pintail (Anas acuta), Gray Plover (Pluvialis squatarola), Common Snipe (Gallinago gallinago), Bristle-thighed Curlew (Numenius tahitiensis), Red-necked Stint (Calidris ruficollis), and Whiskered Tern (Chlidonias hybrida). We discuss previously undescribed vocalizations of endemic taxa and provide online reference to recordings. We also present supporting evidence for the recognition of two taxa as full biological species: Kosrae Fruit Dove (Ptilinopus hernsheimi; formerly part of the P. porphyraceus complex) and Kosrae White-eye (Zosterops cinereus, as a split from Gray-brown White-eye, Z. ponapensis). The avifauna of Kosrae includes 53 naturally occurring species of birds of which 13 breeding residents are extant (2 endemic species, 4 endemic subspecies) and 2 are extinct (both endemic species), 21 are boreal migrants from breeding populations in the temperate Northern Hemisphere (including 11 exclusively Palearctic migrants and 3 exclusively Nearctic migrants), 5 are austral migrants from breeding populations in the temperate Southern Hemisphere, and 12 are visitors from breeding populations on tropical islands elsewhere in the Pacific. Two additional species have been introduced; one has a self-sustaining feral population and the other is extirpated. Because of the island’s low human population and relatively pristine environment, resident breeding birds are thriving with no serious threats to their survival at present, except for overhunting of the Micronesian Imperial Pigeon (Ducula oceanica oceanico).